Isotactic-Alternating, Heterotactic-Alternating, and ABAA-Type Sequence-Controlled Copolyester Syntheses via Highly Stereoselective and Regioselective Ring-Opening Polymerization of Cyclic Diesters
Abstract:Synthesizing different types of sequence-controlled
copolyesters
can enrich the diversity of copolyesters and modify their properties
more precisely, but it is still a challenge to synthesize a complicated
sequence-controlled copolyester using different hydroxy acids in a
living polymerization manner. In this work, a highly regioselective
and stereoselective catalytic system was developed to synthesize biorenewable
and biodegradable copolyesters of mandelic acid and lactic acid with
isotactic-alternating, hete… Show more
“…The thermal and hydrolysis properties of copolyesters are affected by the sequence structure. [9][10][11][12][13][14] In the past decades, metal-based initiators have been widely applied for the stereoselective and regioselective ROP of lactones, which can be used to control the sequence-controlled copolyesters. The stereoselectivity and regioselectivity of initiator/catalyst depend on the confined space formed by the catalytic metal center, monomer, and chain end of the polymer.…”
Section: Doi: 101002/macp202100323mentioning
confidence: 99%
“…[49] In 2021, Wu and coworkers then confirmed that the high regioselective in the ROP of enantiomerically pure MPDD initiated by TMP-Zn, and the least hindered carbonyl group in this asymmetric cyclic diester was proved to be easier nucleophilically attacked (Figure 11). [9] It was meant that isotactic alternating copolyesters of lactic acid and mandelic acid could be obtained by regioselective homopolymerization of enantiomerically pure MPDD. Further study has shown that when THF was used as a polymerization solvent, TMP-Zn has heteroselectivity for the polymerization of rac-MPDD.…”
Section: Stereoselective and Regioselective Roap Of Asymmetric Cyclic Diestermentioning
confidence: 99%
“…Reproduced with permission. [9] Copyright 2021, American Chemical Society. a) The M n and Ð were determined by GPC.…”
Section: Stereoselective and Regioselective Roap Of Asymmetric Cyclic Diestermentioning
The hydrolysis behavior of copolyester is significantly affected by its sequence structure. The crystallinity and melting-transition temperature of sequence-controlled copolyesters also may be different to random copolyesters. Therefore sequence-controlled copolyesters have become an attractive class of materials recently. Through living ring-opening polymerization (ROP), both the molecular weight and sequence structure of copolyesters can be easily controlled. In the past decades, the development of metal-based initiators has greatly promoted research in this field. In this minor review, the recent progress in the ROP of lactones initiated by metal complexes to synthesize copolyesters with a clear sequence structure is summarized. Moreover, the future development of sequence-controlled copolyester synthesis will be discussed.
“…The thermal and hydrolysis properties of copolyesters are affected by the sequence structure. [9][10][11][12][13][14] In the past decades, metal-based initiators have been widely applied for the stereoselective and regioselective ROP of lactones, which can be used to control the sequence-controlled copolyesters. The stereoselectivity and regioselectivity of initiator/catalyst depend on the confined space formed by the catalytic metal center, monomer, and chain end of the polymer.…”
Section: Doi: 101002/macp202100323mentioning
confidence: 99%
“…[49] In 2021, Wu and coworkers then confirmed that the high regioselective in the ROP of enantiomerically pure MPDD initiated by TMP-Zn, and the least hindered carbonyl group in this asymmetric cyclic diester was proved to be easier nucleophilically attacked (Figure 11). [9] It was meant that isotactic alternating copolyesters of lactic acid and mandelic acid could be obtained by regioselective homopolymerization of enantiomerically pure MPDD. Further study has shown that when THF was used as a polymerization solvent, TMP-Zn has heteroselectivity for the polymerization of rac-MPDD.…”
Section: Stereoselective and Regioselective Roap Of Asymmetric Cyclic Diestermentioning
confidence: 99%
“…Reproduced with permission. [9] Copyright 2021, American Chemical Society. a) The M n and Ð were determined by GPC.…”
Section: Stereoselective and Regioselective Roap Of Asymmetric Cyclic Diestermentioning
The hydrolysis behavior of copolyester is significantly affected by its sequence structure. The crystallinity and melting-transition temperature of sequence-controlled copolyesters also may be different to random copolyesters. Therefore sequence-controlled copolyesters have become an attractive class of materials recently. Through living ring-opening polymerization (ROP), both the molecular weight and sequence structure of copolyesters can be easily controlled. In the past decades, the development of metal-based initiators has greatly promoted research in this field. In this minor review, the recent progress in the ROP of lactones initiated by metal complexes to synthesize copolyesters with a clear sequence structure is summarized. Moreover, the future development of sequence-controlled copolyester synthesis will be discussed.
“… 2 Precisely controlled alternating polymer sequences can affect the physical and mechanical properties of polymers and open the door to applications that are not achievable with corresponding homopolymers or gradient or block copolymers. 3 …”
“…However, the synthesis of sequence-controlled polypeptides via polymerization is a long-lasting challenge ( Jones, 2008 ; Lutz, 2010 ; Lutz et al., 2013 ). Therefore, a breakthrough in sequence-controlled poly-α/β-peptide synthesis is highly desired, though sequence-controlled polymerizations are reported recently on the synthesis of polyacrylates, polynorbornene, poly(styrene- b -maleimide) and polyesters ( Jia et al., 2021 ; McGraw et al., 2020 ; Pfeifer and Lutz, 2007 ; Yasir et al., 2020 ). Figure 1 Strategies to prepare poly-α/β-peptides (A) Solid-phase synthesis to prepare α/β-peptide oligomers.…”
Summary
The fascinating functions of proteins and peptides in biological systems have attracted intense interest to explore their mimics using polymers, including polypeptides synthesized from polymerization. The folding, structures and functions of proteins and polypeptides are largely dependent on their sequence. However, sequence-tunable polymerization for polypeptide synthesis is a long-lasting challenge. The application of polypeptides is also greatly hindered by their susceptibility to enzymatic degradation. Although poly-α/β-peptide has proven to be an effective strategy to address the stability issue, the synthesis of poly-α/β-peptide from polymerization is not available yet. Hereby, we demonstrate a living and controlled copolymerization on α-NCA and β-NTA to prepare sequence-tunable poly-α/β-peptides. This polymerization strategy shows a prominent solvent-driven characteristic, providing random-like copolymers of poly-α/β-peptides in THF and block-like copolymers of poly-α/β-peptides in a mixed solvent of CHCl
3
/H
2
O (95/5, v/v), and opens new avenues for sequence-tunable polymerization and enables facile synthesis of proteolysis tunable poly-α/β-peptides for diverse applications.
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